The last time our pipes got blocked socks! were found in the pipe. (Yes, washing machines really do eat socks). This blockage was refusing to budge and as it got dark, work had to be postponed until Monday.
After much more digging and drilling, the cause of our problems emerged.
This is a root of a pepper tree. It had grown on top of our plastic waste pipe and slowly squashed it until nothing much was getting through. I knew that eucalyptus trees shouldn't be built near houses and now I know that neither should pepper trees. I dread to think what they are doing to out foundations. We've found a good plumber, now on the look out for a man with a chain saw.